1. Field of the Invention
The present invention relates to a current sensor capable of measuring target current in a contactless manner.
2. Description of the Related Art
In the field of motor drive technology for electric vehicles and hybrid cars, relatively large current is used. Current sensors capable of measuring large current in a contactless manner are required for such purpose. Current sensors recently developed include a current sensor that allows magnetic sensors to detect a change in magnetic field caused by target current. For example, Japanese Unexamined Patent Application Publication No. 2002-156390 discloses a current sensor that includes magnetoresistive elements as elements for magnetic sensors.
In the above-described contactless current sensor, since the magnetic sensors detect a change in magnetic field caused by target current, slight displacement of installation positions of the magnetic sensors relative to a current line through which the target current flows may result in a large measurement error. The current sensor including the magnetic sensors therefore has to be positioned relative to the current line through which the target current flows with high installation accuracy.
As the accuracy of installation of the current sensor relative to the current line is increased, however, ease of installation of the current sensor is reduced. In the contactless current sensor, therefore, it is difficult to maintain the ease of installation and high accuracy of current measurement.